Re: So what's null then if it's not nothing?

> Consider the question "When did you stop beating your wife?"
>
> Someone who is unmarried can't respond with a date, even though they
> know the answer. The correct answer is Null, but this does not mean that
> the answer is unknown. Any debate that works on the assumption that Null
> necessarily means unknown is based on a false premise and will possibly
> produce paradoxical conclusions.

Well this is exactly the point. It is not the question that we should care about. In fact the question should be almost irrelevant - it's the answers that the database should be concentrating on encoding (and none will be "Null"). Extrapolating out answers for a tweaked question:

"When did meet your wife?" - 2001
"When did meet your wife?" - I am not married
"When did meet your wife?" - I can't remember.

yields 3 facts as a result. And these all fulfill different predicates. Go figure. Yet these forms of responses are so prevalent in human discourse, surely the indication is that the DBMS systems we are currently presented with (by which I refer to the management systems themselves and not the RM underpinnings) are insufficient. Received on Mon Nov 21 2005 - 12:53:54 CET